Anchor escapement for time-measuring instruments

ABSTRACT

An anchor escapement without safety pin, anchor horns and banking means on the anchor and without a small roller on the balance, the improvement of the locking faces of the anchor being prolonged by return faces allowing the anchor in the case of knocking and overbanking an additional angular movement to guarantee an unobjectionable working of the escapement even in the case of shocks and knocking.

I UilltEd [19] Tuetey I 11] 3,826,076 ],.Iuly 30, 1974 [5 ANCHOR ESCAPEMENT FOR.

- TIME-MEASURING INSTRUMENTS [75] Inventor: Paul Tuetey, Le Locle, Switzerland [73] Assignee: Les Fabriques dAssortiments Reunies, Neuchatel, Switzerland 22 Filed: June 19, 1973 [211 A i, No.: 371,412

[30] Foreign Application Priority Data July 19, 1972 Switzerland 10826/72 52 us. C1..... .1 58/116 R [51] Int. Cl. G04b 15/00 [58] Field 01 Search 58/28 D, 116 R.

[56] References Cited UNITED STATES PATENTS 509,315 11/1893 Klahn ..58/l16R' 2,946,227 7/ 1960 Denton et a]. 50/116 R X 3,511,340 5/1970 Sim0n-Vermot.;. 58/121 A 3,611,707 10/1971 Scholz....; 50/116 R 3,738,101 1 6/1973 Simon-Vermot 58/116 R Primary Examiner-Lawrence R. Franklin Attorney, Agent, or Firm-Imirie & Smiley [5 ABSTRACT 7 An anchor escapementwithout safety-pin, anchor' horns and banking means on the anchor and without a small roller on the balance, the improvement of the locking faces of the anchor being prolonged by return faces allowing the anchor in the case of knocking and overbanking an additional angular movement to guar- -antee an unobjectionable working of the escapement even inthe case of shocks and knocking.

11 Claims, 6 Drawing Fignres ANCHOR ESCAPEMENT FOR TIME-MEASURING INSTRUMENTS BACKGROUND OF THE INVENTION won to realize thin, flat watch'movements. The Swiss Pat. No. 101,651 already posed this provlem, but solved it only in an insufficient manner by an escapement without banking means and without the system safetypin-roller. A greatinconvenience of this prior escapementresides in the fact thatthe anchor on its travel is progressively limited by the action of the pallet-stone onto the interior of the toothing of the eskopf-escap'ement. However, since the recoil angles in the entry and in the exit are not the same, it is practically impossible to find a shape of the teeth of .the escape wheel, which at the same time fulfils the conditions of the entry. pallet and of the exit pallet. For this reason, thisprior escapement has never been realized industrially.

I In the escapements accordingto the Swiss Pat. Nos. 289,431 and 395,868 the banking pins or stops form a portion of the anchor body, but the limitation of the oscillations of the anchor takesplace by shock, since no additional angle is possible for this limitation, so that, for guaranteeing a correct manner of working of the escapement, a complete systemof safety pin, horns and roller is necessary. s

SUMMARY OF THE INVENTION It is the aimof the invention to remedy these inconvenienees and to create a satisfactory escapement without safety pin, horns and banking means onthe anchor and without a small roller on the balance and to find a solutionfor' thatpurpose allowing the anchor to work lations, allow the anchor, in the case of knocking or overbanking, an additional angular movement and, In

this way, guarantee an unobjectionable working of the escapement even in the case of shocks and knocking.-

In a special form of performance of the escapement according to the invention the return faces-are curved I in such a way that aconstant or progressively increasing return moment is guaranteed. The return faces are, therefore, in principle convex at the entry and concave at the exit. The value of the return angle, which can be kept constant along the whole supplemental are, is preferably ehosen'between to 25, this value depending on the value of the coefficient of friction of the materials used. This return angle can,'in a progressive wheel.

I capefwheel, sothat its mannerof working can, on the whole, be compared with that of a pin-pallet or Rosmanner, increase to an extent as the additionalangle of the anchor increases, in order to obtain in this way a progressive braking and a rapid return.

The drawings illustrate, byway of examples, two embodiments of the object of the invention with two modifications for the second example.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top view of the first example with a monometallic anchor, in the position in which the entry is in engagement with the escape wheel.

FIG. 2 is a sectional view along the line II-II of FIG.

FIG. 3 is a top view of the first example, in the'postion in which the exit is in engagement with the escape FIG. 4 is'a top view of the second example. i FIGS. 5 and 6 illustrate modifications of the ends of the anchor arms of the second example.

DETAILED DESCRIPTION OF THE INVENTION;

consisting of brass coated by a hard layer 21, such as for instance, of chemical nickel with a hardness of about 600 Knoop or more. The shaft 6 of the anchor 1 is preferably a traditional one. The anchor 1' has neither a safety pin nor horns. .Its arms la and 1b are stamped out in the shape of pallets and constitute function surfaces such as the locking faces 7, the impulse faces 8 and return faces 9. The locking faces 7 and the impulse faces 8 correspond to those of an ordinary anchor. The return face 9 of the arm is serves for bringing the anchor 1 back to and for positioning it in the position shown in FIG. 1, so that a tooth of the wheel 2 is in contact with the entry of the anchor l, with the exception, of course, of the recoil movement and'the impulse released by the roller pin 4 or the oscillation of the balance 5 about its shaft 11 in the direction of the arrow .12 respectively. In the position of the anchor l as shown in FIG. 3, the face 9 of the arm 1 b guarantees that the tooth 10 remainsin' contact with the locking face 7. Although the illustrated escape wheel 2 has not exactlythe shape of that of a so-called Swiss lever escapement, it fulfills nevertheless the same functions.

In a certain point. the return angle 15 lies between the tangent 16 to the return face 9 and the perpendicular 17 to the straight line 18 which connectsth'e said point withthe center of the anchor 1, i.e., with the, geometrical axis of the palletor anchor-shaft 6.

From FIG. 2 it may be seen, that the anchor 1 is very easy tomanfuacture, because it is flat and has no parts fixed to it. For this reason, and since it has no superfluous masses such as horns, safety pins or pallet-stones which are at a large distance from the staff 6, its moment of inertia is smaller than that of a traditional an chor for the same conditions. This results in an improvement of the efficiency of the escapement and in a good running of the watch. v

An improtant advantage resides in the fact that a metallic anchor can be manufactured very easily from one piece at a minimum of operations, such, as for instance, stamped or punched and afterwards finished. Furthermore, the anchor can be manufactured without diffi- 3 culties by injection molding. Both, the monometallic anchor andthe injection-molded anchor can be provided with a hard layer 21, in order to improveits resistance against wear and tear and/or the coefficient of friction between the anchor 1 and the escape wheel 2. Instead of consisting of chemical nickel, the layer 21 may, for instance, also be made of hard chromium or of a Co-Re alloy.

In the occurrence as shown in FIG. 4 the metallic pallets of FIG. 1 which are formed bythe anchor arm ends, are replaced by pallet-stones 118 and 119 fixed to the anchor and made of ruby or of any other hard and/or self-lubricating material. The return faces 120 are provided on the arms 116a and 116b of the anchor body 116. In the modification shown in FIG. 5 besides the pallet-stones 119 also members 130 comprising the return faces are fixed to the anchor. Pallet-stones 119 and members 130 may consist of ruby, or other hard and/or self-lubricating material. In the modification illustrated in FIG. 6 the pallet-stones 131 consisting of r'uby or any other hard and/or self-lubricating material comprise all the necessary faces, viz: the impulse face 128, the locking face 117 and the return face 120. of the embodiment according to FIG. 4.

The working of the escapement according to the invention will now be described with reference to FIGS. 1 and 3:

. The return faces 9 limit the amplitude of the oscillations .of the anchor 1. Experience has proved that during the normal mannerof'working of the escapement, the travel of the anchor 1 is stopped when the heel of a tooth reachedthe line of intersection between the locking face 7 and the return face 9. However, if necessary, the return faces 9 allow the anchor 1 to run through an additional angle. This occurs on the occasion of outer shocks or of knocking. If the impulseor roller-pin 4 of the large roller 3 is in the position of FIG. 1, a shock in the direction of arrow 26 (FIG. 3) may bring the fork from the position of FIG. 1 into the position of FIG. 3. During this movement, the tooth 10 is brought out of engagement at the entry and the wheel 2 beginsv to move until the tooth 10 contacts at the exit the locking face 7 of the exit-pallet lb. If the roller-pin v 4 moves in the direction of the arrow 33 (FIG. 3) the balance runs without hindrance. However, if the rollerpin 4 moves in the direction of the arrow 33 (FIG. 3), it strikes against the back of the fork. In a normal anchor without safety pin and without roller the watch would come to a standstill. This phenomenon is called overbanking. However, in the case of the escapement according to the invention the impulseor roller-pin 4 5 runs through an angle of more than 360. In this case,

pushes the edge of the lefthand fork arm forward and the fork arm finally allows the roller-pin 4 to pass it, since the anchor 1, due to the retum face 9 at the exit, pushes the escape wheel 2 backwards while the face 9 glides on the heel of the tooth 10.

As soon as the impulseor roller-pin 4 has passed the fork arm, the tooth 10 at the exit lb, under the influence of the mainspring of the'watch, pushes the return face 9 forward and allows the anchor 1 to take again its position of function according to FIG. 3. On its return the roller-pin 4 finds the fork again in its correct position, ready to receive an impulse. I

The escapement according to the invention also offers security of its working in the case of the so-called knocking. Knocking occurs when the mainspring of the watch is oversized. If such an oversized mainspring is the roller-pin 4 of a classical escapement when moving in the direction of the arrow 33 (FIG. 3) strikes against the backside of the horns or fork arms and is heavily repulsed, which in certain cases can result in a tearingout or breaking of the roller-pin 4. In the escapement according to the invention, however, the anchor, on the roller-pin 4 sticking against the backside 34 of the fork,

. gives way as in the case of overbanking and continues its travel. In this way, another phenomenon, impairing the running of the watch, is done away with.

On the ccurrence of the two above-mentioned phenomenona the escapement according to the invention counts exactly the number of vibrations of the balance, so that any advance in the running of the watch is avoided.

I claim: v

1. An anchor escapement for time-measuring instruments with a balance and animpulse means connected with the balance, an escape wheel, an anchor cooperating with said escape wheel and with said impulse means, said anchor having first and second opposite arms, each of said arms terminating in a locking face and an impulse face to cooperate with the teeth of said escape wheel, the improvement wherein said anchor further comprises a return face on the terminal portion of each arm adjacent said locking face, each said return face being disposed at an acute angle relative a perpendicular to a straight line between the axis of the anchor and the intersection of said return and locking faces, said return faces cooperating with the teeth of said escapement wheel to limit the oscillations of said anchor while allowing the anchor, in the case of knocking and overbanking, an additional angular movement to guarantee an unobjectionable working of the escapement even in the case of shocks and knocking.

2. An anchor escapement as claimed in claim 1, said return faces extending along a curve establishing a constant'return moment between the anchor and the escape wheel.

3. An anchor escapement as claimed in claim 1, said return faces extending along a curve establishing a progressively increasing return moment between the anchor and the escape wheel. 1

4. An anchor escapement as claimed in claim 1, said acute angle lying between 10 and 25.

5. An anchor escapement as claimed in claim 1, said anchor being monometallic and coated by a layer of a hardness of at least 600 Knoop.

6. An anchor escapement as claimed in claim 5, said layer consisting of chemical nickel.

7. An anchor escapement as claimed in claim 5, said layer consisting of hard chromium.

8. An anchor escapement as claimed in claim 5, said layer consisting of a Co-Re alloy.

9. An anchor escapement as claimed in claim 1, two pallets fixed to the body of said anchor and comprising said locking and said impulse faces, said return faces being provided on the body of said anchor.

10. An anchor escapement as claimed in claim 1, two pallets fixed to the body of said anchor and comprising said locking and said impulse faces, and two separate members fixed to the body of said anchor, said return faces being provided on said separate members.

11." An anchor escapement as claimed in claim 1, two pallets fixed to the body of said anchor, each of said pallets comprising an impulse face, a locking face and a return face.

d (snarl) f\ UNITED STATES, PATENT- OFFICE CERTIFICATE OF CORRECTION Patent No. 3,826,076 Dated Jul} 3 97 4/ Inventor-(s) f5": "Paul Tuetey It is certified that error appears in the above-ideritified patent and that said Letters Patent are hereby corrected as shown below:

.The assijeghee should read Les Fabriques d'Assortim'e'nts Reunies, Le ,Locle, Canton of Neuchate l' r lSwitzerland -4- I n cla im l", line 33 please change "escapeme nt" to escape Signed and sealed this 14th day of January 1975.

Attest I McCOY M; GIBSON JR. Attesting Officer 0. MARSHALL DANN Commissioner of Patents USCOMM-DC 60376-1 69 we" Po-wso uo-ss) e v ".5. GOVERNMENT PRINTING OFFICE 1 Q. ""3"'3" UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. "3,826,076 Dated July l3, 197

. I/ Inventor(s) Paul Tuetey It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

The assignee should read Les FaIariques d'Assortiments Reunies, Le Locle, Canton of NeuchateL switzerland In claim l,-- line 33 please change "escapement" to escape Signed and sealed this 14th day of January 1975.

(SEAL) Attest:

McCOY M. GIBSON JR. c. MARSHALL DANN Attesting Officer Commissioner of Patents USCOMM-DC 60376-PG9 =ORM PO-IOSO (10-69) 1 w u.s. sovurmzu'r PRINTING omc: nu o-au-su 

1. An anchor escapement for time-measuring instruments with a balance and an impulse means connected with the balance, an escape wheel, an anchor cooperating with said escape wheel and with said impulse means, said anchor having first and second opposite arms, each of said arms terminating in a locking face and an impulse face to cooperate with the teeth of said escape wheel, the improvement wherein said anchor further comprises a return face on the terminal portion of each arm adjacent said locking face, each said return face being disposed at an acute angle relative a perpendicular to a straight line between the axis of the anchor and the intersection of said return and locking faces, said return faces cooperating with the teeth of said escapement wheel to limit the oscillations of said anchor while allowing the anchor, in the case of knocking and overbanking, an additional angular movement to guarantee an unobjectionable working of the escapement even in the case of shocks and knocking.
 2. An anchor escapement as claimed in claim 1, said return faces extending along a curve establishing a constant return moment between the anchor and the escape wheel.
 3. An anchor escapement as claimed in claim 1, said return faces extending along a curve establishing a progressively increasing return moment between the anchor and the escape wheel.
 4. An anchor escapement as claimed in claim 1, said acute angle lying between 10 and 25*.
 5. An anchor escapement as claimed in claim 1, said anchor being monometallic and coated by a layer of a hardness of at least 600* Knoop.
 6. An anchor escapement as claimed in claim 5, said layer consisting of chemical nickel.
 7. An anchor escapement as claimed in claim 5, said layer consisting of hard chromium.
 8. An anchor escapement as claimed in claim 5, said layer consisting of a Co-Re alloy.
 9. An anchor escapement as claimed in claim 1, two pallets fixed to the body of said anchor and comprising said locking and said impulse faces, said return faces being provided on the body of said anchor.
 10. An anchor escapement as claimed in claim 1, two pallets fixed to the body of said anchor and comprising said locking and said impulse faces, and two separate members fixed to the body of said anchor, said return faces being provided on said separate members.
 11. An anchor escapement as claimed in claim 1, two pallets fixed to the body of said anchor, each of said pallets comprising an impulse face, a locking face and a return face. 